Technological Field
The present invention relates to an image reading apparatus for separating and conveying documents one by one from a bundle of sheet-like documents, and reading images from these documents. Furthermore, the present invention relates to an image forming apparatus equipped with the image reading apparatus.
Description of the Related art
Examples of a conventional image reading apparatus and a conventional image forming apparatus include those described in JP 2011-010050 A. In the apparatus of JP 2011-010050 A, documents separated one by one are conveyed by a “reading entrance roller 16” and a “reading exit roller 23”. The document passes over a “translucent member 21” while the document is conveyed, and the image is read at that time (paragraphs [0034] to [0036], FIG. 4 of JP 2011-010050 A). JP 2011-010050 A further includes “cleaning means 301”. The “cleaning means 301” is provided with a “cleaning member 305”, a “white plate 303”, and a “black plate 304” (paragraph [0058] of JP 2011-010050 A). The “cleaning member 305” cleans the upper surface of “translucent member 21”. The “white plate 303” and the “black plate 304” are provided to detect foreign materials.
However, the above-described conventional technique has a problem in that the reading speed cannot be increased to a sufficiently high speed. In the apparatus of JP 2011-010050A, it is necessary to completely retract the “cleaning means 301” from the reading position when the document to be read passes the reading position. From this state, between a gap between documents (between sheets), it is necessary to bring the “black plate 304” of the “cleaning means 301” to the reading position and retract the “black plate 304” of the “cleaning means 301” back to the original position again. Therefore, it is impossible to shorten the space between the documents to a narrow distance. It may also possible to use the “black plate 304” to detect the end portions in the width direction of the reading document, but it is actually impossible to do so. This is because the document is not configured to pass between the “black plate 304” and the “translucent member 21”.